Electronic circuits exposed in operation to large variability of, for example, input voltage (that is large input swings) have been an area of extensive research and development over the years.
Buffer circuits for digital-to-analog or analog-to-digital converters (DACs or ADCs) are exemplary of possible applications of such circuits.
Despite that intensive activity in that area, further improved solutions are still desirable, for example, in respect of one or more of the following aspects:                availability of flexible solutions suited for use in any circuit exposed to large input voltage swings,        improved performance when used in DACs or ADCs,        possibility of using input transistors of a voltage class lower than the supply voltage (for example, 1.8V v. 3V),        facilitated use in a wide variety of circuits such as, for example, High Voltage—HV operational amplifier (OpAmps).        
There is a need in the art to contribute in providing such an improved solution.